In a scroll compressor, an orbiting scroll that constitutes a compression mechanism together with a fixed scroll is generally configured such that the orbiting scroll fitted to the outer periphery of a drive bearing is driven so as to orbit around the fixed scroll, via a driving mechanism that includes a crank shaft having a crank pin at a shaft end, a drive bush fitted to the crank pin, and the drive bearing fitted to the outer periphery of the drive bush.
In this scroll compressor, there is a problem in that, because gas pressure imposed on the orbiting scroll during operation is always imposed at a fixed position of the drive bush, concentrated surface fatigue occurs at one position of the drive bush, thus shortening the lifetime of the drive bush. PTLs 1 to 3 describe technologies in which a cylindrical ring (floating bush) is rotatably fitted to the outer periphery of the drive bush in order to avoid this concentrated surface fatigue occurring on the surface of the drive bush to extend the lifetime of the drive bush.
In the above-described cylindrical ring (floating bush), one end thereof is brought into contact with a step portion of the drive bush to prevent detachment, and the other end (shaft end) thereof is prevented from being axially detached by a retaining plate fixed at the tip of the crank pin via a snap ring or by a retaining ring mounted in a tip groove of the crank pin so as to be partially engaged with the cylindrical ring (see PTLs 1 to 3).